Summary/Abstract The Lymphatic Forum 2019 is the 2nd in a planned conference series that bring together researchers from around the world that study lymphatics in health and disease. The lymphatic vascular system is a relatively understudied, yet vital component of the cardiovascular system that couples the tissue parenchyma to the venous blood via lymph flow through a complex network of lymphatic vessels. It transports fluid, macromolecules, lipids, tissue catabolic products and immune cells/agents as lymph. Thus, the lymphatic system provides critical links for the transport of fluid, macromolecules, cells and other elements from the interstitial space of all organs to and through the lymph nodes to the venous blood. In completing this transport, it regulates body fluid volume, macromolecular homeostasis, immune function, inflammation and lipid absorption/metabolism. It is a specialized vascular system with a complex network of low pressure vessels with unique mechanisms to form and transport lymph. The lymphatic system serves as both a complex network of lymph conduits and as a series of unique intrinsic lymph pumps that generate and regulate the lymph flow that drives all of its functions. Because of its unique, complex structural and functional characteristics, it has been difficult to examine and quantify its structure and function in the body. However a better understanding of its structure and function is important to health and disease. Other international/national lymphatic biology conferences, including the previous Lymphatic Forum 2017 focused predominantly on the embryologic development, lymphangiogenesis, lymphatic endothelial cell function and relationships to cancer and immunity. The conference plan outlined in this application is unique in that it is the first that has a significant focus on quantitative aspects of the principal function of the lymphatic vascular system ?lymph transport. It pays particular attention to the complex aspects of lymphatic vascular system such as; biomechanics of lymphatic development, structure and function, lymphatic growth and remodeling in pathological states, the mechanisms of lymph flow generation and regulation, the most common & unique lymphatic cell- lymphatic muscle, quantitative/computational analyses of complex lymphatic structures and function/flow and the relationships between the inflammation & the lymphatic and immune systems. Thus, the lymphatic system is an intrinsic, understudied part of the cardiovascular system that influences health and disease and this conference is relevant to the missions of the NHLBI and NIBIB. Additionally, the conference is specifically designed such that trainees and young investigators have significant roles.